Lignocellulosic biomass is the most abundant renewable material on the planet and has long been recognized as a potential feedstock for producing chemicals, fuels, and materials. Lignocellulosic biomass normally comprises primarily cellulose, hemicellulose, and lignin. Cellulose and hemicellulose are natural polymers of sugars, and lignin is an aromatic/aliphatic hydrocarbon polymer reinforcing the entire biomass network.
Biomass refining (or biorefining) has become prevalent in the world's economy. Cellulose fibers and sugars, hemicellulose sugars, lignin, syngas, and derivatives of these intermediates are being utilized for chemical and fuel production. Integrated biorefineries are capable of processing incoming biomass much the same as petroleum refineries now process crude oil. Underutilized lignocellulosic biomass feedstocks have the potential to be much cheaper than petroleum, on a carbon basis, as well as much better from an environmental life-cycle standpoint. Over the past few years, several commercial-scale biorefineries have been constructed, designed to convert lignocellulosic biomass such as corn stover, wheat straw, and sugarcane bagasse or straw into so-called second-generation ethanol.
However, there remains a need for improved conversion technologies to produce second-generation ethanol. What is needed is a low-cost, practical approach to render lignocellulosic biomass easily accessible to cellulase enzymes, to produce fermentable sugars.